Filters



June 9, 1959 c. MACKINTOSH FILTERS 2 Shets-Sheet. 1

Filed March 22, 195'? INVENTOR ATTORNEYS June 9, 1959 C. MACKINTOSHFILTERS Filed March 22, 1957 2 Sheets-Sheet 2 R m m V m ATTORNEYS UnitedStates Patent FILTERS Charles Mackintosh, Los Angeles, Calif.

Application March 22, 1957, Serial No. 648,470 12 Claims. (Cl. 210-450)This invention relates to filtering devices and more particularly todevices of this type which embody filter packs or cartridges whichcomprise alternate laminations of fabrics and supporting and spacingwebs.

The general object of the invention is to provide a novel and improvedfiltering device of the class described which is relatively simple andinexpensive to construct and use but one which will serve eifectively toseparate solid or semi-solid impurities from water and other liquids.

The invention in its preferred embodiment contemplates the provision ofa novel filter of this class which is especially efiicient in filteringand re-filtering the water of swimming pools, although the invention maybe applied to other analogous uses. The preferred mode of prac tice ofthe invention envisions the preparation of a plug or cartridge fittedsnugly within a suitable container or enclosure having inlet and outletducts associated therewith and preferably one or more closures or accessmeans through which a used cartridge can be removed and a fresh oneinstalled. Back-washing action may also be provided for in any known orsuitable way.

Each of such cartridges comprises an approximately cylindrical volutelaminated package, formed by rolling up one or more compound sheetsconsisting of layers of generally laminar filter medium and corrugatedboard; preferably with the filter sheet doubled and embracing one edgeand a portion of each side of the corrugated board.

When tightly rolled the volute assembly is fitted into the containerwhich is arranged toconduct the flow of the fluid to be filtered in anaxial direction with respect to the assembly. Any small axially locatedpassage or bore which may be left in the rolled assembly due to possiblestiffness of the material of which it is formed, may be filled by a plugof either filter material or of impervious material, such as, forexample, an axial bolt for retaining the cartridge or container closurein place.

Further objects of the invention include the provision of variations inthe volute laminated filter, one of which contemplates the provision ofa filter member consisting of two layers, one comprising filter paper,which in this case may be of relatively weak wet strength, and asupporting and reinforcing mesh placed in close contact with the paperand both of them being arranged with relation to the stifiening sheet asalready mentioned.

Another embodiment of the invention includes the utilization as a filtersheet of a mesh lamination confining a thin layer of granular filter-aidbetween itself and the wall of the corrugated stilfening sheet.

A further variation includes the impregnation of the folded portion ofthe doubled filter sheet with a stifiening or hardening composition inorder to strengthen the sheet at this point.

Other objects and features of novelty will be apparent from thefollowing specification when read in connection with the accompanyingdrawings in which certain embodiments of the invention are illustratedby way of example.

, In the drawings:

Patented June 9, 1959 forming the package and taken on line 4-4 ofFigure 3;.

Figure 5 is a vertical diametric sectional view taken through thecompleted package and substantially along line 5-5 of Figure 3;

Figure 6 is a greatly enlarged view as compared with the previousfigures and showing the axial opening at the central zone of the packagewhich is to be filled by any of the means described;

Figure 7 is a view on a smaller scale of one exemplary.

embodiment of the filter container in which the novel filter package orcartridge is inserted;

v Figure 8 is a fragmentary view in perspective of a section of a filterdevice according to another embodiment of the invention, the devicebeing shown before it is rolled into final form;

Figure 9 is a similar view illustrating a still further embodiment ofthe invention; and

Figure 10 is a view similar to those shown in Figures 8 and 9illustrating a still further variation employing partly impregnatedfilter paper.

In Figures 5 and 7 the completed volute filter cartridge is designatedgenerally by the reference numeral 10 and in Figure 7 it is shownenclosed in a typical casing or con tainer to which is applied thegeneral reference character 11.

Perhaps the best way to describe the filter package 10 which forms apreferred embodiment of the invention is to delineate the steps taken inpreparing the package. Thus in Figure 1 there is shown an elongated web12 of filter paper or filter cloth upon which has been laid a strip orweb of ordinary flexible corrugated board 13. Preferably the lamination13 is treated by coating or impregnation with material which will causeit to retain its structural configuration and not collapse when immersedin water.

It will be noted that the corrugated reinforcing web or laminationextends only approximately half way across the filter sheet 12 and isalso oifset inwardly from the terminal end 17 of the filter sheet.Purely by way of suggestive illustration of certain proportionings whichmay characterize one embodiment of the invention, it is suggested thatthe width of the filter strip 12 may be in the neighborhood of, say,twelve inches and the width of the reinforcing strip 13 approximatelyeight inches.

In Figure 2 the manner in which the filter web 12 is folded over thereinforcing sheet 13 is shown. The filter sheet 12 is doubled andextends over the major portion of each side of the lamination 13 wherethis lamination occurs. If the dimensions suggested above are adheredto, the folded width of the filter sheet 12 will be approximately sixinches and the extension of the uncovered edge of the spacing sheet orlamination 13 will be about two inches.

Referring now to Figures 3 and 4 it will be seen that two assemblies ofsheets 12 and 13 are placed together one on top of the other and withthe uncovered edges of the intermediate sheets 13 extending in oppositedirections and prolonged beyond the edge of the other assembly. This isshown particularly in Figure 4 of the drawings where the upper assemblyA extends somewhat further to the left than the lower assembly B, and inthe reverse overlapping position at the right-hand edge.

It will also be noted from an inspection of Figure 3 that/the upperassembly A terminates at the peripheral portion of the rolled-up packagesome distance short of the termination of the layer B. This arrangement,to gether with the extension of the inward or axial edge of the filterpaper portions of both assemblies as suggested at the left-hand end ofFigure 2, greatly'facilitates the initial Winding adjacent the axis ofthe assembly and the termination of the winding at the periphery of theassembly so as to cause it to fit well within the casing '11 withoutdangerous leakage around the package adjacent the inner wall of thecontainer.

Figure 5 shows very clearly the nature of the rolled-up package. It mustbe borne in mind throughout an ex amination of the drawings that due tothe requirement for showing even very thin sheets of material in sectionor with double-line thickness, the relative thickness of the laminationswith respect to the full dimensions of the package is very considerablyexaggerated.

An inspection of Figures 5 and 6 will reveal the nature of the inner oraxial winding of the material. For purposes of more specificidentification, the reference character x is applied to the innerextension of the filter paper strip which occurs at the axis of thedevice when the package is rolled up, and the reference character y isapplied to the extension of the fi'lter paper or cloth 12 which willoccur at the periphery of the package. Thus, the nature of thepreliminary winding at x is clearly shown in Figures 2, 5 and 6 and thenature of the extension y is best shown in Figures 3 and 5.

The axial opening z shown clearly in Figures 5 and 6 maybe plugged withany suitable filter material or with impervious material depending uponthe nature of the installation. However, in the suggested example shownin Figure 7 this void 2, is occupied by the axial bolt 20 which extendsbetween the end covers 21 and 22 of the casing 11 which encloses thefilter assembly 10. The end structures 21 and 22 are flanged as at 24 toembrace the cylindrical wall 25 of the casing and each end structure maybe provided with inlet and outlet nipples 26 through which the water orother liquid vto be filtered is made to pass. The tie bolt 20 may bethreaded at each end and nuts 27 applied thereto.

In rolling up the laminations to form the substantially cylindricalpackage pleats may be folded in the upper face of the laminations asrequired during the rolling operation. It will be noted that the upperface of the lower layerwill pleat itself automatically as therollingproceeds. It will be noted that the filter as formed isreversible and fiow can proceed in either direction. The liquid to befiltered will pass axially edgewise through the corrugations of theseparator strip 13 and when reaching the opposite edges about which isfolded the filter medium, the liquid will pass through and any solidmaterial will be retained. As to the lamination A or B which is disposedoppositely to the initially mentioned lamination the liquid willencounter the folded edge of the filter paper first and then pass intothe corrugations of the separator strip. However, it will be seen thatthese folded edges are preferably indented a short distance inwardlyfrom the protruding open edges of the separator strips and solidmaterial will be collected in such indentations.

The filter may be cleaned by backwashing, or in the case of its use as aswimming pool water filter it may be cleansed by merely dowsing thepackage or assembly in a bucket of water or holding it under a gentleflow of water from a faucet or tap.

In Figure 8 of the drawings there is illustrated a variation in theinvention which involves the provision of a filter device 30 adapted tobe Wound in spiral form preferably in conjunction with a similar deviceas in the preceding embodiments, and which includes the same type ofcorrugated stilfening lamination 31 as described in connection with theearlier embodiment. The filter sheet in this embodiment is itselflaminated and consists of a layer of filter paper or filter cloth shownat 32 and a layer -of reticulated material or mesh indicated at 33,

4 i 1 these layers being placed in close contact and doubled about theedge of the corrugated supporting sheet 31. In this example the layer 32may be of relatively weak filter paper and the mesh may be of anysuitable filamentary material whether metal or plastic, the material ofcourse being selected with respect to the possibility of corrosion bythe liquids ibeing filtered.

In Figure 9 of the drawings the filter device which is wound into voluteform, preferably in conjunction with a strip of similar construction, isindicated generally by the reference numeral 40 and comprises the usualcorrugated stiffening sheet 41 and a filter layer doubled around thesheet 41, which layer consists of an outer mesh or reticulated sheet 42within which, and surrounding both sides of the stiifening sheet 41, isa layer of granular filter-aid material 43. This material may be of anysuitable or known type whether of perlitic composition or not, and thisparticular arrangement has been found to.

be very useful when the filter is to be 'backwashed.

In Figure 10 of the drawings the laminations comprismg the filter device50 are quite similar to those described in the embodiment illustrated inFigures 1-6 of the drawings in which the co gated stiffening sheet 51has a layer of filter fabric 52 doubled about it, but in this instancethe folded portion of the sheet of paper or other fabric 52 isimpregnated, as indicated at 53 with a stiffening material. This may beapplied by dipping the paper or fabric in a suitable liquid, or paintingit with such a liquid, and then allowing the liquid to dry and harden bygelation, evaporation, oxidation, or otherwise. Examples of suchmaterials useful for preparing filters for various purposes are varnish,shellac, plastic solut1ons, dissolved waxes such as parafiin, etc.

It will be understood that various changes and modifications may be madein the embodiment illustrated and described herein without departingfrom the scope of the invention as determined by the following claims.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. filter for use in clarifying water and other liquids comprising, incombination, a substantially cylindrical casing having inlet anddischarge openings for the liquid adjacent the respective opposite endsthereof, filter material disposed in said casing, said materialcomprising a cartridge of the same generally cylindrical peripheralconfiguration as the inner wall of the casing and adapted to fit snuglyagainst said inner wall, the casing adjacent the periphery of saidcartridge being imperforate, said cartridge formed of volute rolled-upsuperposed laminatlons of filter sheets and sheets of spacing material,which latter material is liquid-pervious edgewise thus transmltting theliquid axially between the filter sheets, said filter sheets beingdoubled about said spacing sheets enveloping one end edge of the latterbut extending along said spacing sheets to points short of the oppositeend edge, the outer surfaces of the filter sheets of adjacentlaminations being in close contact, and the cartridge also beingimpervious to axial flow of liquid except along the spacing sheets andthrough the juxtaposed filter sheets.

2. The filter set forth in claim 1 in which the cartridge comprises twoassemblies of filter sheets and spacing sheets rolled up together involute form and substantially identical except for the enveloped edgesand exposed edges of the spacing sheets being reversed in the twoassemblies.

3. The filter set forth in claim 1 in which the spacing sheet comprisesa corrugated material of sufiicient rigidity to maintain generally itsconfiguration within the liquid to be filtered.

4. The filter set forth in claim 3 in which the spacing sheet iscomposed of ordinary flexible corrugated board.

5. The filter as set forth in claim 1 in which the filter sheet itselfis in turn laminated and comprises a layer of thin filter fabric and ajuxtaposed layer of supporting and reinforcing mesh material, bothenveloping the spacing sheet edge as described.

6. The filter as set forth in claim 5 in which the filter fabric ispaper of relatively weak wet strength, and the mesh material is ofmetallic wire.

7. The filter as set forth in claim 1 in which the filter sheetcomprises a sheet of filter paper impregnated at the folded portion witha liquid material which upon drying leaves a stiffening residue upon thepaper, whereby the major portion at least of the liquid passes throughthe adjacent laminations of the filter paper, and the folded portionsare strengthened at the points where they are in contact with the endedges of the corrugated board.

8. The filter as set forth in claim 1 in which the filter sheetcomprises a mesh layer retaining a layer of granular filter-aid betweenitself and the adjacent surfaces of stiifening spacing sheet.

9. The filter as set forth in claim 2 in which the two laminated layersare oifset axially whereby the edges of the separator sheets which arenot covered by the folded filter sheets protrude from their respectiveends of the laminated cartridge, leaving the opposite edges which arecovered by the folded filter sheets indented within said cartridge.

10. The filter as set forth in claim 2 in which the layers of filtersheets are longer than the layers of separator material before winding,and extend beyond the ends of the latter material at both the axialcentral portion of the wound-up cartridge and the periphery thereof.

11. The filter as set forth in claim 1 in which a plug is positionedaxially through the cartridge to prevent any seepage of liquid throughany central axial opening left after the winding of the rolledcartridge.

12. The filter as set forth in claim 1 in which said plug comprises abolt for securing the cartridge in the container.

References Cited in the file of this patent UNITED STATES PATENTS1,861,576 Liddell June 7, 1932 2,173,978 Pennebaker Sept. 26, 19392,394,895 Burhans Feb. 12, 1946 2,427,733 McCann Sept. 23, 19472,525,330 Zaun Oct. 10, 1950 FOREIGN PATENTS 1,065,017 France Dec. 30,1953

